Transient Analysis of a Line-Start Synchronous Reluctance Motor with Symmetrical Distributed Brass Rotor Bars

Abstract

In this paper, the performance evaluation of a line-start three-phase Synchronous Reluctance Motor (SynRM) with symmetrical distributed brass rotor bars is presented. The machine, which has been designed from a conventional three-phase induction motor (IM) NEMA frame stator is proposed as an alternative to a squirrel cage induction motor (SCIM). The 2D Finite Element Analysis (FEA) under ac magnetic transient solution was used to study some performance parameters of interest during starting transients. The experimental measurements were carried out in order to validate the numerical computation, to analyze the starting transients, and to explore the dynamic responses due to load variations. The FEA and experimental results of the synchronous reluctance motor with brass rotor bars (SynRM-BRBs) are compared to the results of a conventional threephase SCIM of the same NEMA frame stator. The results evidenced that the reluctance torque developed by the SynRM-BRBs has a compounding effect on the accelerating torque, reaching its steady-state operational condition faster than the SCIM. The dynamic response of the SynRM-BRBs is faster in contrast to the SCIM during load variations. Furthermore, it was noted through measured results that the proposed line-start three-phase SynRM had a reduced dynamic no-load, and load current as opposed to the SCIM, thus positioning itself as a good candidate to replace the SCIM in applications that require a line-start ac motor with good starting transients and fast dynamic responses.

Line-Start Synchronous Reluctance Motor With V-Shaped Rotor Laminations

“…where 𝜌 = (𝑑/𝑑𝑡), the subscripts s and r indicate the variables associated with the stator and rotor respectively, while the superscript r refers to the rotating reference frame, 𝜆 𝑠𝑑 and 𝜆 𝑠𝑞 are the d-and q-axis stator flux-linkages, 𝜆 𝑟𝑑 and 𝜆 𝑟𝑞 are the d-and q-axis rotor flux-linkages, 𝜔 and 𝜔 𝑟 are the synchronous and rotor speeds, in electric radians respectively. The two values of rotor resistance for d-and qaxis in ( 6) and ( 7) contemplate the non-isotropic character of the LS-SynRM rotor [27]. The flux-linkages equations are expressed by [25], [27]:…”

“…The two values of rotor resistance for d-and qaxis in ( 6) and ( 7) contemplate the non-isotropic character of the LS-SynRM rotor [27]. The flux-linkages equations are expressed by [25], [27]:…”